Question

Does the following Java code guarantee an exclusive lock on an unopened file in Windows?

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class Test {
    public static void main(String[] args) {
        File file = new File("mylog.log");
        try {
            FileOutputStream fos = new FileOutputStream(file);
            fos.getChannel().lock();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 1

As may be seen in Java specs:

File locks are held on behalf of the entire Java virtual machine. They are not suitable for controlling access to a file by multiple threads within the same virtual machine.

So if you need exclusive lock for the thread, please choose another way.